1 files changed, 45 insertions, 0 deletions
diff --git a/testing/web-platform/tests/intersection-observer/padding-clip.html b/testing/web-platform/tests/intersection-observer/padding-clip.html
new file mode 100644
index 0000000000..0126304d64
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+++ b/testing/web-platform/tests/intersection-observer/padding-clip.html
@@ -0,0 +1,45 @@
+<!doctype html>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<title>Scrollport is used rather than content rect to compute intersection ratio</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="author" href="https://mozilla.org" title="Mozilla">
+<link rel="help" href="https://github.com/w3c/IntersectionObserver/issues/504">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+#root {
+  overflow: hidden;
+  position: relative;
+  box-sizing: border-box;
+  width: 100px;
+  height: 100px;
+  padding: 10px;
+}
+#target {
+  width: 100px;
+  height: 100px;
+  background-color: green;
+  /* Shift into the padding area */
+  position: relative;
+  left: -10px;
+  top: -10px;
+}
+</style>
+<div id="root">
+  <div id="target"></div>
+</div>
+<script>
+promise_test(async function(t) {
+  const target = document.getElementById("target");
+  assert_true(!!target, "target exists");
+  const root = document.getElementById("root");
+  assert_true(!!root, "root exists");
+  const entries = await new Promise(resolve => {
+    const observer = new IntersectionObserver(resolve, { root });
+    observer.observe(target);
+  });
+  assert_equals(entries.length, 1, "Should have one entry.");
+  assert_equals(entries[0].intersectionRatio, 1, "Should be completely visible.");
+});
+</script>